Another Fuel Pump Problem

[Meriden]

Hi All,

 

My RT has been getting little use over the past couple of years and the last time it was ridden was three or four months ago. At that point it was running fine. I needed to get a safety inspection and the bike wouldn't start so I went through the usual procedure. Spark was okay. I replaced the fuel for good measure. There is power at the electrical connector to the fuel pump on pin 2 and pin 1 is grounded properly. Fuses 5 and 6 along with relays 5 and 6 are both good. The pump does not run. It can't be heard when the bike is turned on and it does not pump fuel with an injector removed. The Hall Sensor was replaced about 15k ago so I'm not suspecting that. The fuel pump was replaced about the same time, but it has been siting in old gasoline for a few months now. 

 

What is unusual is the fuel gauge is not working any longer either. The bike turns over so I suspect the side stand switch is not the problem.

 

What am I missing?

 

Thanks

m 

[dirtrider]

1 hour ago, Meriden said:

Hi All,

 

My RT has been getting little use over the past couple of years and the last time it was ridden was three or four months ago. At that point it was running fine. I needed to get a safety inspection and the bike wouldn't start so I went through the usual procedure. Spark was okay. I replaced the fuel for good measure. There is power at the electrical connector to the fuel pump on pin 2 and pin 1 is grounded properly. Fuses 5 and 6 along with relays 5 and 6 are both good. The pump does not run. It can't be heard when the bike is turned on and it does not pump fuel with an injector removed. The Hall Sensor was replaced about 15k ago so I'm not suspecting that. The fuel pump was replaced about the same time, but it has been siting in old gasoline for a few months now. 

 

What is unusual is the fuel gauge is not working any longer either. The bike turns over so I suspect the side stand switch is not the problem.

 

What am I missing?

 

Thanks

m 

Afternoon Meriden

 

The fuel pump ONLY runs for about 2 seconds at key-ON then doesn't run again until the engine is actually cranking. 

 

Are you figuring this into your diagnostics? 

 

Is the fuel pump getting 12v power for a couple of seconds at key-ON (checked with a meter) at key on?

If not then you need to find the reason why.  

 

If the pump IS getting 12v for that 2 seconds then is the pump ground resistance free? You also need to check this.  You can run a ground circuit voltage drop from the fuel pump brown wire to the battery negative post to see if your ground side has issues.  

 

Your pump could be seized up, or possibly it isn't getting 12v supplied to it, or the fuel pump pass through (plate pump is mounted on) is not passing 12v through it's solder connections, or you could have a pump/fuel gauge grounding issue (they share a common ground). Or you could have a bad fuel pump, or ???

 

You have to figure out what you are missing then tell us so we can then advise you on how to repair it. 

 

 

[Meriden]

37 minutes ago, dirtrider said:

Afternoon Meriden

 

The fuel pump ONLY runs for about 2 seconds at key-ON then doesn't run again until the engine is actually cranking. 

 

Are you figuring this into your diagnostics? 

 

Is the fuel pump getting 12v power for a couple of seconds at key-ON (checked with a meter) at key on?

If not then you need to find the reason why.  

 

If the pump IS getting 12v for that 2 seconds then is the pump ground resistance free? You also need to check this.  You can run a ground circuit voltage drop from the fuel pump brown wire to the battery negative post to see if your ground side has issues.  

 

Your pump could be seized up, or possibly it isn't getting 12v supplied to it, or the fuel pump pass through (plate pump is mounted on) is not passing 12v through it's solder connections, or you could have a pump/fuel gauge grounding issue (they share a common ground). Or you could have a bad fuel pump, or ???

 

You have to figure out what you are missing then tell us so we can then advise you on how to repair it. 

 

 

Hi dirtrider,

Thanks for the response and I'm glad to see you are still around. I recall your helpful posts from years ago when I first bought the bike and was sorting it out.

So to answer your questions. Yes, I am counting the 2 second pump start up. I am used to hearing it and can see the power to the green/white #2 wire when I turn on the key. Oddly though the multimeter does not show the power going off after two seconds. 

The brown ground wire shows 0 ohms between the female (chassis) side of the plug and the negative pole of the battery as well as against the frame. If there is a ground problem it is between the male side of the plug and the pump.

Just a few minutes ago I ran 12 volts to the pump direct from the battery. No activity. I am assuming that even if the Motronic turns off the ground to the relay, a direct 12volts to the pump wiring would cause the pump to start. 

I'm beginning to think that I need to pull the tank and inspect the pump. Bad news since I have a half full tank of fresh gas and the inspection is due by the end of the month. 

 

I hope that points to something that I missed. 

 

thanks

mike

 

[dirtrider]

27 minutes ago, Meriden said:

Hi dirtrider,

Thanks for the response and I'm glad to see you are still around. I recall your helpful posts from years ago when I first bought the bike and was sorting it out.

So to answer your questions. Yes, I am counting the 2 second pump start up. I am used to hearing it and can see the power to the green/white #2 wire when I turn on the key. Oddly though the multimeter does not show the power going off after two seconds. 

The brown ground wire shows 0 ohms between the female (chassis) side of the plug and the negative pole of the battery as well as against the frame. If there is a ground problem it is between the male side of the plug and the pump.

Just a few minutes ago I ran 12 volts to the pump direct from the battery. No activity. I am assuming that even if the Motronic turns off the ground to the relay, a direct 12volts to the pump wiring would cause the pump to start. 

I'm beginning to think that I need to pull the tank and inspect the pump. Bad news since I have a half full tank of fresh gas and the inspection is due by the end of the month. 

 

I hope that points to something that I missed. 

 

thanks

mike

 

Afternoon Mike

 

With B+ to the green/white wire at the pump connector & the brown (ground) side ohming  out OK back to the battery (-) post then your problem sure sounds like it is either in the pump itself or in the pump pass-through plate pass-through soldered connections. 

 

If you were just using a voltmeter & the pump side is open circuit then that 12v you were seeing on your meter past 2 seconds was probably just low amp bleed-through from other controlled circuit relays.    

 

Either way you are probably going to have to remove the pump & pump plate to investigate. 

 

One thing you might try is to run 12v & ground to the pump connector then pound on the fuel pump side of your fuel tank with the palm of your hand. If the pump is stuck that m-i-g-h-t shake it free. 

[Meriden]

I'll give it a try and report back with the final results. 

 

Thanks for the insight.

 

m